Update understanding on diagnosis and histopathological examination of atrophic gastritis: A review

Table 1 Comparison of autoimmune atrophic gastritis and Helicobacter pylori-associated atrophic gastritis

Characteristic	Autoimmune atrophic gastritis	H. pylori-associated atrophic gastritis
Etiology	Autoimmune destruction of parietal cells[4,5]	Chronic infection by H. pylori[8,10]
Gastric acid secretion	Reduced, leading to hypo/achlorhydria[3]	Initially increased, but later reduced as atrophy progresses[9]
Location of atrophy	Body and fundus of the stomach[4,5]	Antrum and body of the stomach[12,43]
Serum markers	High gastrin, low pepsinogen I/II ratio, presence of antibodies against parietal cells[4,5]	Positive anti-H. pylori antibodies, variable pepsinogen I/II ratio[43,44]
Gastric microbiota	Altered, with decreased diversity[13,14]	Altered, often with increased colonization by non-H. pylori species[13,15]
Risk of gastric cancer	Increased risk, particularly for neuroendocrine tumors[36,39]	Increased risk of adenocarcinoma, particularly intestinal type[10,12]
Associated conditions	Pernicious anemia, other autoimmune diseases like thyroiditis[4,33]	Gastric ulcer, duodenal ulcer, and MALT lymphoma[6,10]

MALT: Mucosa-associated lymphoid tissue; H. pylori: Helicobacter pylori.